To override the plugin settings on a specific page, you can use a shortcode or a PHP function to create a button with modified parameters. For instance:
[save_as_pdf_pdfcrowd button_text="Customized Text Label"]
will create a button with a modified button label. Click the "Show Parameters" button in the plugin settings to see the parameters and their documentation. There is also the reference documentation for Save as PDF WP Plugin and Save as Image WP Plugin.